CD_4^+自然杀伤T细胞在慢性乙型肝炎病毒感染中的作用

Clinical significance of peripheral blood CD_4^+ natural killer T cells in chronic hepatitis B virus infection

目的 了解CD+ 4、CD+ 8自然杀伤 (NK)T细胞在慢性HBV感染者外周血中的分布情况 ,并对其细胞毒性进行分析 ,阐明其在慢性HBV感染中的作用。方法 常规分离外周血单个核细胞(PBMCs) ,用重组人白细胞介素 12 / 2 (rhIL 12 /IL 2 )诱导 14d ,以鼠抗人CD4 单克隆抗体 (mAb)或抗人CD8mAb与抗人CD56mAb分别标记细胞样品 ,流式细胞术 (FCM)分析 ,CD+ 4CD+ 56同时阳性的细胞 ,即为CD+ 4NK T细胞 ;CD+ 8CD+ 56同时阳性的细胞为CD+ 8NK T细胞 ,因此获得CD+ 4、CD+ 8NK T细胞的百分比。并对细胞样品同时进行细胞毒性试验 ;分别以鼠抗人CD4 mAb、抗人CD8mAb及抗人CD56mAb和新鲜兔血清处理细胞 ,以鉴定CD+ 3 CD+ 4NK T、CD+ 3 CD+ 8NK T细胞的细胞毒活性。结果 rhIL 12 /IL 2诱导后 ,慢性HBV感染者外周血CD+ 4NK T细胞的含量远低于正常对照组。CD+ 4NK T细胞的比例(% )在正常对照组、慢性乙型肝炎 (CH)组和慢性无症状携带者 (AsC)组分别为 18 10± 4 2 0 ,6 95±2 85和 1 5 0± 1 30 ,经方差分析证实 3组之间差异具有显著性 (P <0 0 5 ) ;CD+ 8NK T细胞的比例 (% )在正常对照组、CH组及AsC组分别为 2 70± 1 10 ,2 2 0± 1 40和 3 10± 0 70 ,经方差分析显示 3组之间无统计学差异 (P >0 0 5 )。

Objective To demonstrate the clinical significance of CD + 4 /CD + 8 natural killer T (NK T) cells in chronic hepatitis B virus (HBV) infection, we investigated the proportion and cytotoxicity of CD + 4 /CD + 8 NK T in the peripheral blood of chronic HBV infected individuals. Methods Peripheral blood mononuclear cells (PBMCs) from chronic HBV infected individuals were separated routinely and stimulated with recombinant human interleukin 12/2 (rhIL 12/IL 2) for 14 days, the percentage of CD + 4 NK T cells in peripheral blood was analyzed with fluorescence activated cell sorter (FACS). The cytotoxicity of peripheral blood lymphocytes (PBLs) was tested with a 4 h 51 Cr release assay. Results After IL 12/IL 2 induction, the percentage of CD + 4 NK T cells was 18 10±4 20, 6 95±2 85 and 1.50±1.30 in the healthy controls, chronic hepatitis(CH) patients and asymptomatic carriers (AsC) respectively. The percentage of CD + 4 NK T cells in the peripheral blood of chronic HBV infected individuals was lower than that in the healthy controls. Statistic analysis suggested there was significant difference among the three groups (P<0.05). The percentage of CD + 8 NK T cells was 2.70±1.10, 2.20±1.40和3.10±0.70 respectively in the three groups and there was no significant difference among them(P>0.05). In vitro cytotoxicity assays against Raji cells revealed that the cytotoxicity of PBLs in the healthy control group was more potent than that in CH and AsC group (P<0.05). Cytotoxicity of PBLs in AsC group was significantly lower in comparison with CH and healthy control groups. The cytotoxicity of CD + 4 NK T cells against Raji cells was abolished by treating PBLs with either mouse anti CD 4 antibody or anti CD 56 antibody and complement, and partially depleted by anti CD 8 antibody. Conclusions The abnormal cellular immune function in chronic HBV infected individuals may be associated with deficiency of CD + 4 NK T cells.